Luiz Felipe Scolari admitted that he was worried by aspects of Chelsea's form after they dropped their 12th point at Stamford Bridge and suffered their fourth defeat in 10 matches.

The aura of invincibility that Chelsea had at the start of the season has now disappeared although Scolari believes that the Premier League title race may well go right down to the final games of the season next May.

"We lost three more points and, in the last five games, we've not played well," said Scolari. "We didn't shoot the ball many times in goal as before. And that's my mistake and the players' mistake.

"After, we say something and they discuss it, we did not play well enough to win. They understand that. They know they didn't play well. But now I need to say: 'Finish. We finish this game. We lost three points.'

"I have one week to work with these players and will put the same team against Bolton because no injuries and I try to work this week better than the week before, to arrive many times in front of goal as we did five games ago."

Scolari, though, admitted that he was struggling to understand the reasons behind Chelsea's dip in form.

"The training is normal – it's not tiredness," he said. "They play hard games, but it's not tiredness. They play Wednesday and Sunday. They have recovered very well. They are in good condition."

After conceding two goals following aerial balls from Arsenal, Scolari said: "It's a worry. When I receive the statistics from last season, we made some mistakes at corners and free-kicks last season.

"Until now, we've been in good condition. This was one time that we lost the game on that and against Bordeaux. I'll try and work to start again on this. In England, many clubs play long ball, high balls, and we need to win these balls. We need to work this week.

"I need to say to my players: 'When we play away, we need to win.' We are in good condition in the Premier League, but we need to win more in Stamford Bridge because, away, we have a good statistics.

"We need to follow again when we play against Bolton, win again, and after try to win in Stamford Bridge.

"Manchester United, Arsenal, Chelsea, Liverpool play for first position. The games in the final few weeks might decide who is first in the Premier League."